Light sensitive device



Original Filed Sept. 7, 1940 lNvENToR Car-w Hall er, J1: Hemlglac stone Patented Nov. 19, 1946 i LIGHT SENSITIVE DEVICE Curtis Hillyer, Jr., and Henry Blackstone, Richmond Hil1,'N. Y.

Original application September 7, 1940, Serial No. 355,708. Divided and this application March 6, 1941, Serial No. 381,950

(Cl. Z50-165) Claims.

This invention relates to a light sensitive device,` and more particularly to a photo-emissive tube of the gas filled alkali metal cathode type.

Tubes of the character under consideration are inherently frangible and are often used in the control circuits of various types of devices which, because of their nature, or because of the conditions under which they are used, often subject the tube to excessive shock or vibration. Phototubes are inherently delicate in structure, and conventional tubes are unable to withstand the forces resulting from such shocks and vibration, and either are immediately put out of commission thereby, or deteriorate rapidly thereunder, or have their sensitivity affected to such an extent as to ruin their response. Phototubes, furthermore, occasionally must be so installed that because of the inertia of their glass envelopes they are subject to fracture through their inability to resist forces applied perpendicularly thereto. Still other tubes, particularly those havwhich is generally indicated at i0, comprises a glass envelope generally indicated at II, within which is disposed an anode I2 and a plurality of cathodes I3, respectively seated on and secured to glass pinches or supports I4, preferably formed integral with and extending from the bottom and sides of glass envelope II (see Figure 3). An insulated conductor I5 extends through each of glass supports I4, and is electrically connected to the cathode supported thereon (Figure 1).

Referring back to Figure 1, envelope I I is preferably mushroom-shaped so that the top IIa thereof is substantially nat and has a wide angle of view to permit maximum illumination of cathodes I3. The bottom IIb of envelope II is preferably fiat, while the sides IIc have a relatively short radius of curvature, for a purpose to be disi closed hereinbelow. Envelope sides IIc and boting a plurality of cathodes, are unable to stand up under strains induced by shock and Vibration, by reason of the tendencies of the cathodes to crumble or bend as their inertia resists the 'applied forces. It is accordingly one of the objects of this invention to provide a phototulce which is strong and durable, and accordingly capable of withstanding sudden jarring shocks, or continued excessive vibration. Other objects will be in part apparent and in part pointed out hereinafter.

The invention accordingly consists in the features of construction, combinations of elements and arrangements of parts as will be exemplified in the structure to be hereinafter described and the scope of the application of which will be indicated in the following claims.

In the drawing, wherein there is shown one embodiment of our invention,

Figure 1 is a sectional elevation of the phototube;

Figure 2 is a sectional elevation taken along the line 2 2 of Figure 1;

Figure 3 is a rear perspective view of the phototube, portions thereof being broken away; and,

Figure 4 is a front perspective View of the phototube, certain portions thereof being broken away.

Similar reference characters refer to similar parts throughout' the various views of the drawing.

This application is a division of our application Serial No. 355,708, iiled September 7, 1940. With reference to Figure 1, our phototube,

tom I Ib are mounted in a shock mount I6, which may be made of any suitable material, such as felt or other fibrous substance. Shock mount I6 is in turn secured within a generally cup-shaped housing generally indicated at I'I, which is preferably formed in two parts, namely a bottom I8 and side I9. An annular flange 20 is formed on housing bottom I8 and is complementary to a flange 2l formed on the bottom of housing side I9, these two flanges being secured together in any suitable manner to form the unitary mounting Il. The upper portion of housing side I9 is preferably crimped to provide an inwardly extending retaining ilange 22, which securely holds envelope II and shock mount I 6 within housing Il. It might also be noted, that flanges 20 and 2| of housing I1 provide convenient means for seating the phototube upon installation thereof. Also, housing bottom I8 is suitably drilled to provide passage for conductors I5.

Extending perpendicularly from bottom IIb of envelope II is an integral glass stud 23 on which anode I2, which is preferably in the form of a cylindrical column, is mounted in a position coaxial with the envelope. The left-hand end of anode I2, as viewed in Figure 1, is supported by stud 23 adjacent envelope bottom IIb, whereas the right-hand end thereof abuts envelope top IIa and accordingly provides a support therefor to resist forces applied axially of the phototube which might otherwise fracture the envelope. The anode itself being metallic and cylindrical in form, is inherently capable of withstanding such shocks, and as tube bottom Hb rests flatly against shock mount I6 and housing bottom I8, it too is well able to withstand these forces. Also, as noted above, sides llc of the tube enve- 3 lope have a rather sharp curvature which together with the support provided by shock mount I renders the envelope sides substantially shatterproof from shock or vibration.

Glass supports I4 are preferably formed integrally with envelope side llc and extend radially and inwardly therefrom toward anode l2 (Figures l and 2). The inner edges Ilia of glass supports I4 are preferably parallel to and spaced from anode I2, so that if there is any slight relative movement between the anode and glass stud 23, there will be no danger of contact between the metal anode and glass supports. it might also be noted that supports I4 are also preferably integral with envelope bottom I Ib and extend upwardly therefrom, The tops Ilib of the supports are preferably flat and have extending therefrom L-shaped posts 24 which are fused in the glass and which are suitably secured as by welding to cathodes I3 to support the cathodes in proper position on supports I. As noted before, conductors I are also fused within the supports and are secured to cathodes I3 so as to make good electrical connection therewith.

Cathodes I3 are formed of suitable metal, and eachincludes preferably a flat top i3d (Figure 4) of substantial area which, as is more clearly shown in Figure 1, is spaced from edge Iiib of support I4. Cathode top ISa (Figure 3) has extending rearwardly therefrom integral, tapered stiffening flanges |319 and I3c provided with notches 25 and 26, respectively, into which the top of support ILS extends to prevent movement of the cathode transversely of its support. Flanges I3?) and I3c are deepest at the central portions thereof.' Hence, these flanges are generally of a cantilever construction, which providesY suicient rigidity to withstand bending forces generated by shocks imparted perpendicularly to the cathode. As may be seen in Figure 4, cathodes I3 may be generally wedge-shaped, but preferably terminate at their inner edges short of anode I2, so as to provide ample space between the anode and cathodes to preclude engagement in the event of relative movement therebetween.

It may Vnow be seen that top lla of the tube envelope II is amply supported by anode I2, that envelope sides IIc and bottom iIb are well supported by shock mount Iii and housing I'I, and yet, 'interior leakage paths of substantial extent over'the glass surface are provided. Inasmuch as supports I4 lie in planes. parallel to or extending through the axis of the phototube, they are not subjected to any bending forces which might cause them to crack, but are subject only to 'forces of compression which they are well able to withstand. By reason of the cantilever character of cathode flanges I3b and iSc, such bending forces as the cathodes are subjected to are sufficiently resisted so that the cathodes are sustained against distortion.

Accordingly we have provided a photo-emissive tube which efficiently fulfills the objects hereinbefore referred to.

As many possible embodiments may be made of 'the above invention, and as many changes might be made in the embodiment above set forth, it is to be understood that all matter hereinbefore set forth, or shown in the accompanying drawing, is to be interpreted as illustrative and not in a limiting sense.

We claim:

1. A phototube comprising, a glass envelope, a rigid anode mounted within said envelope and 4 bearing at its ends against the envelope walls to support them against collapse, a photocathode, and means mounting said cathode in said envelope adjacent said anode, said cathode having a flat top of substantial area lying in a plane passing through the axis of said anode. Y

2. A phototube comprising, a glass envelope, a rigid anode centrally mounted within said envelope and bearing at its ends against the envelope walls to support them against collapse, a plurality of photocathodes, and means mounting said cathodes in said envelope around said anode, said cathodes having flat tops of substantial area lying in a plane which passes through the axis of said anode.

3. A phototube comprising, a glass envelope having a relatively flat top and bottom, a rigid anode centrally mounted within said envelope and bearing at its ends against said envelope top and bottom to support them against collapse, a plurality of photocathodes, and means mounting said cathodes in said envelope about said anode, said cathodes having iiat tops of substantial area lying in a plane parallel to the plane of said envelope bottom.

il. A phototube comprising, a glass envelope, a tubular rigid anode mounted within said envelope and bearing at its ends against the envelope walls to support them against collapse, one of said envelope walls including a portion projecting into said anode to maintain said anode in position within said envelope, a photocathode,'and means mounting said photocathode in said envelope adjacent said anode.

5. vA phototube comprising, a glass envelope, a glass support in said envelope lying in a plane passing through the axis thereof, a second glass support disposed in said envelope coaxially therewith, a planar photocathode secured to said first glass support with the plane of said cathode passing through the axis of said second glass support, and a tubular anode Vmounted on said second glass support adjacent said cathode and engaging the top of said envelope in supporting relation thereto.

6. A phototube comprising, a glass envelope having a bottom, an integral glass stud formed on said bottom and extending therefrom within said envelope coaxially therewith, a tubular anode mounted on said glass stud, a plurality of glass supports in said envelope, each of said supports lying in a plane passing'through the axis of said anode, and a photocathode mounted on each of said supports, said cathodes all lying in a plane passing through the aXis of said anode between the ends thereof.

'7. A phototube comprising, a glass envelope, a plurality of glass supports integrally formed with said envelope and lying therewithin, each of said supports lying in a plane passing through the Vaxis of said envelope, a planar photocathode mounted on each of said supports, all of said cathodes lying in a general plane passing through said axis, and an anode mounted within said envelope centrally of said cathodes with the planes of said cathodes also passing through said anode between the ends thereof.

8. A phototube comprising, a glass envelope, a glass support in said envelope'lying in a plane passing through the axis thereof, a photocathode having a tapered flange depending therefrom and engaging said glass support, means secured to said glass support and mounting said cathode thereon, and an anode secured within said envelope adjacent said cathode.

9. A phototube comprising, a housing, a glass envelope having a at bottom and a relatively at top, means forming a shock mount between said housing and the bottom and sides of said envelope, and an anode and photocathode mounted within said envelope, said anode being rigid and bearing at its ends against the top and bottom of said envelope to support them against Collapse.

10. A phototube comprising, a glass envelope 10 having integral sides, top and bottom, an elongated rigid anode mounted within said envelope coaxially therewith and supporting said top and bottom, a plurality of at photocathodes, and means mounting said cathodes in said envelope around said anode with said cathodes lying in a plane normal to the axis of said anode.

CURTIS HILLYER., JR. HENRY BLACKSTONE. 

